A new continuous flow cell has been designed and built so that combined optical and Resonance raman spectroscopy can be used to monitor potentiometric titrations of cytochrome oxidase. In connection with these experiments, a new technique for controlling electrode voltages and/or currents has been developed. Use is made of computer I/O cards rather than analog circuit devices as used in the past. Software to accomplish this purpose, as well as to perform and monitor the titrations has been developed. In order to use the technique of singular value decomposition (SVD) to deconvolute kinetic spectra during the rapid turnover of cytochrome oxidase, a new ultra rapid spectrometer has been designed and built. The necessary software to control the instrument has been developed. This spectrometer will be capable of accumulating and storing sequential optical spectra with a time resolution of 10 (mu)sec. SVD has been used to analyze kinetic spectra obtained with bacteriorhodopsin, which was activated with different light intensities. We find that the light appears to "titrate" two centers which affect the kinetic properties of intermediates in the cycle.